Diagnosis of dengue fever: roles of different laboratory test methods

Background: Dengue fever is currently the most important arthropod borne viral disease. Since occurrence of dengue infections has been an epidemic in many parts of India and complications like DHF and DSS are increasing, while at the same time the diagnosis is challenging, particularly the laboratory diagnosis is confusing, this study was conducted to evaluate the different laboratory test methods and to compare their respective efficacy, timing, advantages and disadvantages. Methods: This study was done in the Department of Microbiology in collaboration with the Department of Medicine and Pediatrics in two tertiary care medical colleges and hospitals in eastern India. Blood samples from 319 patients with clinical features suggestive of Dengue fever were included in this study. Laboratory investigations were done which included immunological assays that were performed using commercially available kits - SD dengue duo NS1Ag + Ab combo rapid test, NS1 Ag capture ELISA, IgM capture ELISA, IgG capture ELISA test for dengue and other routine tests -full blood cell count, coagulation tests, routine biochemical and lipid profile were also done. Ethical considerations were taken care of and statistical evaluations were done. Results: An increased detection of IgM antibody (46.15%) was seen in the early febrile period (1-5 days) as compared to the mid-febrile period (6-10 days), and late febrile period (6-10 days) when it is 6.89%. IgG antibody is much less in early febrile period (4.16%). Compared to mid-febrile period (24.13%), and late febrile period (62.5%). IgM antibodies were detected in 44.5% of the samples, IgG antibodies were detected in 43.5% of the samples, Rapid test was positive in 36.9% and NS1AG ELISA was detected in 43.5% of the samples in the study. Conclusions: It can be inferred from our study that for detection of dengue in the early febrile period (1-5 days), estimation of dengue-specific serum IgM is the most sensitive antibody detection method.